How would I link in with the celcon blocks, which are designed for
3x65mm + 20mm mortar ?
Furfix fittings. Thick beds or adjustable ties.

Me's thinking, BCO would fuss about thick beds on the celcon, since
this would reduce the
insulation spec. I guess a real bricky just fiddles with things as he
goes along.
I would want to design the blocks and tie layout before hand so I know
how they are going to fit.
Might be tricky since outer skin beds would be higher than usual, but
the ties must slope outwards rather than inwards.
Cheers,
Simon.